Principle diagram of micro-nano fiber coupled superconducting nanowire single photon detector
Superconducting nanowire single-photon detector (SNSPD), as a high-performance single-photon detector, has been widely used in quantum information, laser radar, deep space communications and other fields, effectively promoting the related fields Technology development.
There are two kinds of optical coupling modes in SNSPD devices, one is vertical optical coupling mode, the optical fiber end face is parallel to the SNSPD photosensitive plane, and the photons are incident perpendicularly to the nanowire, and the optical cavity or the mirror structure is used to realize high-efficiency optical coupling. Coupling structure, the Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences has achieved NbN-based SNSPD system detection efficiency over 90%, after the publication of relevant results of widespread concern at home and abroad. The optical coupling structure is characterized by high optical coupling efficiency can be achieved, but Limited by the optical coupling structure, the working wavelength range is limited.Other optical coupling method is the waveguide optical coupling method, the preparation of the nanowires on the optical waveguide, can achieve efficient intrinsic absorption.But the fiber to the waveguide coupling efficiency than Low, making such devices only as a solution to on-chip photonics that can not be used as a standalone single-photon detector.
Shanghai Institute of Microsystem / Chinese Academy of Sciences Center for Excellence in Superconductivity Innovation Youleixing researcher team and Zhejiang University professor Fang Wei, Tong Limin team, first proposed micro-nano-fiber coupled SNSPD device structure. The structure of SNSPD devices placed in the micro-nano Optical fiber in the evanescent field, to achieve nanowires in the transmission of micro-nanofiber photonic absorption.Optical calculations show that this type of structure is expected to achieve high absorption efficiency, while maintaining good broad-spectrum characteristics.After the Shanghai micro-system Witch doctor Jun Jie and Zhejiang University Ph.D. Xu Yingxin and other nearly three years of experimental exploration, research team developed a micro-nano-fiber coupling SNSPD device. In 1550nm / 1064nm working wavelength, the system detection efficiency of 20% / 50% respectively. Related results recently published in Optics Express This result is expected to open up new research directions in the field of novel SNSPD devices and micro / nano optical fibers.
Research has been the key national R & D project 'high-performance single-photon detection technology', the Chinese Academy of Sciences strategic pilot science and technology (B) 'superconducting electronic device application basic research', the Natural Science Fund and the Shanghai Municipal Science and Technology Commission and other funding.
